The invention relates to a filter system having a filter element, in particular for use as an air filter of an internal combustion engine, and a filter element for fitting in such a filter system.
The structure of filter systems in which round filter elements are used is known from the prior art. In use, flow through the round filter elements frequently takes place from the outside to the inside, wherein the filtered fluid is fed out of the cylindrical inner chamber through an opening in the cover or bottom of the round filter element to the output of the filter housing. The diameter of the output opening in the cover of the round filter element is limited by the diameter of the inner chamber of the filter element. This is given by the diameter of the filter element minus the pleat height of the filter medium used.
On the one hand, a greatest possible pleat height allows for a large effective filter area of the filter element with constant external dimensions. On the other hand, the output opening for the filtered fluid must have an adequate cross section to be able to discharge the fluid. With specified dimensions of the filter element, a choice must therefore be made between these two design influences and a compromise must be found.
Conically shaped filter elements, which, however, have a larger installation space requirement due to the conical shape, which opens with a certain angle in the opposite direction to the outlet direction of the filter system, are disclosed in EP 1558360 B1. Pleated secondary elements, which, however, take up additional installation space compared with secondary elements with smooth filter media, are also known.
An object of the invention is therefore to design a compact filter system having at least one replaceable filter element made of a filter medium in such a way that a highest possible separation rate for dust particles can be achieved with favorable installation space.
A further object of the invention is to create a filter element for fitting in such a filter system, with which a highest possible separation rate for dust particles can be achieved with favorable installation space.